Predictors of cardiac responsiveness to fluid therapy after cardiac surgery.

摘要

OBJECTIVES: Central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) are insensitive preload markers and sometimes misleading. The introduction of the pulse contour method for monitoring of continuous cardiac output enabled the real-time quantification of stroke volume variation (SVV). Studies evaluating the accuracy of this parameter as a measure of preload responsiveness are still limited and conflicting results have been published in cardiac surgical patients. The aim of this study was to reevaluate the predictive value of SVV regarding cardiac responsiveness to fluid therapy and to compare it with the standard preload variables in a clinical setting in the ICU after cardiac surgery. METHODS: The assessment of cardiac responsiveness to fluid therapy (HAES-steril 6% 10 mL * Body Mass Index) was performed in 92 ventilated coronary artery surgical patients after arrival in the ICU. After the fluid load, detailed hemodynamic measurements were performed. A 'responder' was defined as a patient with a gain in stroke volume index (SVI) of 5% or more from baseline value to the volume challenge. RESULTS: Post hoc analysis showed that there were 47 responders to the fluid challenge and 45 non-responders. Hemodynamic data before the fluid therapy show that stroke volume variation in the responders group was significantly higher than in the non-responders groups (9.7 +/- 4.3% versus 7.6 +/- 3.0%, P = 0.01). The receiver operating characteristic curves for the baseline values of CVP, PCWP and SVV were constructed for illustrative purposes. The area under the curve for baseline values of SVV was significantly higher than random guess (area = 0.65, p < 0.05), indicative for the value of SVV as a marker of cardiac responsiveness to fluid therapy. The static preload parameters CVP and PCWP had no predictive value. CONCLUSION: SVV as measured with the LiDCO system is a better functional marker of cardiac responsiveness to fluid therapy than the static parameters CVP and PCWP.